What Is A Combi Boiler?

A combi boiler provides heating and hot water directly from the boiler.

Here’s an example of a central heating and hot water system layout using a combi boiler:

A combi (or combination) boiler is an ingenious space-saving idea, and an increasingly popular choice in UK homes. In fact, combis now account for well over half of all the new domestic boilers installed in Britain every year.

A combi boiler is both a high-efficiency water heater and a central heating boiler, combined (hence the name) within one compact unit. Therefore, no separate hot water cylinder is required, offering space saving within the property.

Further benefits of a combi boiler are significant savings on hot water costs and the fact that hot water is delivered through your taps or shower at mains pressure. So you can enjoy powerful showering without the need for a pump.

Another combi boiler benefit is that it can generally save you money on installation time and costs, since no tank in the roof space means less pipe work and a shorter installation time.

Combi Boilers such as the Worcester Greenstar 24i Junior 100280 Combi Boiler offer up to 90.1% efficiency and boast a grade A efficiency rating and gives a maximum heat output of 24kW to the central heating system and offers instant hot water as well as a keep hot feature.

Ideal for smaller homes and apartments the 24i Junior offers 9.8 litres per minute of hot water at 35 degrees. It also boasts highly flexible flue options and a wall-mounting frame to hide the unsightly pipework.

It also boasts a variety of control options ranging from the basic mechanical to the all-singing, all dancing digistal that features automatic daylight savings time adjustment, 24 hour functionality as well as a programmable room thermostat to accurately control the temperature of the house.

And a recent survey revealed that 9 out of 10 professional installers would choose Worcester for their own homes*. All of which gives you the reassurance of knowing that when you invest in a
Worcester product, its quality is endorsed by the professionals.

As domestic boilers currently account for 21%* of the UK’s total CO2 emissions, the fact that a Worcester condensing boiler also delivers dramatically reduced emissions of both CO2 and NOx (Nitrogen Oxide) helps in the battle against climate change. All Worcester Greenstar boilers are within class 5 – the lowest of the 5 categories – for NOx emissions.

Go Green And Save Money

Our homes generate a quarter of the UK's CO2 emissions, yet a third of the energy we use is wasted. It's time to act, but what is truly practical and affordable for us to do? And can we save some money while we're at it? Channel 4 Homes Helps Us Take A Look Into How We can cut carbon emissions and save money.

The Loft

Up to a quarter of a home's heat can escape through the roof if it's badly insulated. According to the Building Research Establishment, if you were to put down 270mm of insulation in an empty loft, you'd save £145 a year. The greenest option would be to insulate it with natural, environmentally friendly products. These include Warmcel 100, made from recycled paper; Isonat Plus, made from UK-grown hemp and recycled cotton; and Thermafleece, which comes from UK sheep. You can buy all of them from EnergyWays at www.naturalinsulations.co.uk.

There are reductions to be made on insulation measures for home owners and landlords, as part of the government's Carbon Emissions Reduction Target (CERT). Contact your local Energy Saving Trust Advice Centre to see what's on offer. For more advice on insulation, see Fitting Insulation

Cost: £250 (installed); £50-£350 (DIY)
Return: Two to three years

The Walls

Like roofs, walls can also leak up to a third of the heat produced in your home. The government is very keen on cavity wall insulation at the moment, so grab a grant while you can. It takes less than a day to install, there's minimal disruption, and it could save you £110 a year on fuel bills, according to the Energy Saving Trust. Ideally, opt for eco-friendly Warmcel.

If your home was built before or around the 1920s, it probably has solid walls, and around 45% of heat is lost through them. Insulation is expensive and usually worth considering only when you're refurbishing, though it could save you £375 a year on fuel bills. Internal insulation consists of rigid insulation boards or a stud wall, and costs £5,500 to £8,500. External insulation consists of a layer

of insulating material attached to walls then finished with cladding or render, cost £10,500 to £14,500. Find a registered installer at The Insulated Render & Cladding Association (INCA).

Cost: (cavity walls) around £250 including CERT subsidy (see above); otherwise around £500
Return: Two years

Draught Proofing

Around 20% of all heat loss in a typical home is through ventilation and draughts. Obviously, some ventilation is essential, especially if you have solid-fuel or gas fires, but don't forget that wherever you can feel a draught coming in, warm air is going out.

Save around £25

by draught proofing doors and windows, and around £20 extra if you fill gaps between the floorboards and skirtings as well.

Cost: £100 if you do it yourself
Return: Four years (or one year if you do the floorboards and skirting, too)

Buying New Equipment

Appliances

Don't forget to look out for the official energy rating when you're buying a new appliance. 'A', 'A+' and 'A++' rated is good, but don't bother if it's less than 'B' or 'C'. It's difficult to cost out the saving, but as an example, an 'A' rated freezer or washing machine will only use a third of the energy of one with a lower rating. Sneak Preview: I'm told The new House 2 Home Megastore has some very efficient appliances that will be available for purchase when the site launches completely, which, i'm told is getting nearer everyday.

Saves: from £7 (for integrated digital TV) to £38 (for a fridge freezer)
Cost: Depends what you buy
Return: Four years

The Boiler

If you're thinking of installing a new one, go for it as soon as possible! Around 60% of all domestic CO2 emissions come from old boilers. New rules say boilers should have an 'A' efficiency rating, which basically means having a condensing boiler.

Save up to £235 by replacing an old G-rated boiler with a new A-rated one and installing a full set of heating controls.

Cost: From £650 (plus £600 to £800 for installation)
Return: Four years

Lightbulbs

Is your ceiling filled with those pretty little halogen bulbs? Each one uses 50w, while energy-efficient bulbs use up to four times less electricity to generate the same amount of light. Each one will save around £9 on your annual bill.

Cost: from 50p
Return: Within a year

Double Glazing

This will reduce heat loss by half and knock £130 a year off the average bill. Look for the energy-saving recommended logo, and if money's not a factor, choose Argon-filled triple-glazed timber-framed windows made with low-emissivity glass (look for the 'A' to 'G' energy rating and Forest Stewardship Council certification for the frame). 'If you are on a budget, secondary glazing that fits inside the existing frame is much more cost-effective and can reduce heat loss,' says Sally Oakes from the Centre for Alternative Technology.

Cost: £400 per unit
Return: 20 years+

How To Choose A New Boiler

It might not be as exciting as the new Cappuccino Maker or the Wide Screen TV but the boiler is one of the most important pieces of technology in your home. 4Homes have got together with www.house.co.uk to bring you a guide to the world of hot water and warm homes.

There's the mournful shaking of the head, the quick sucking in of air between the teeth and then the phrase every home owner dreads "Oooh dear. You're going to need a new boiler here and no mistake".

It's enough to strike a chill into the stoutest heart. However not only are boilers probably less expensive than you think they're also a key part of the home.

With a good boiler you can have a plentiful supply of heating and hot water provided efficiently and economically. An old or unsuitable boiler is likely to leave you with ever increasing heating bills, while making you vulnerable to a system that is unable to provide hot water to more than one outlet at the same time (we've all been there - the shower goes cold as someone starts doing the washing up in the kitchen) or packs up completely if someone dares try to have a bath while the heating is on.

The Energy Saving Trust recommend that you should think about replacing your boiler after 15 years. Whilst boilers beyond this age can often still function, their effectiveness and efficiency becomes reduced.

Boilers over fifteen years old can have an average efficiency of around 65%, this is compared to over 90% efficiency offered by "A" rated condensing boilers from British Gas.

The first thing to decide when choosing a boiler is what sort of fuel you're going to use - town gas, LPG (Liquified Petroleum Gas) or oil. Then you need to decide on the size of the boiler, measured in BTU (British Thermal Unit) or Kilowatts, the number of radiators, the type of hot water system and whether you're planning to upgrade your system.

How To Choose

It is important to take advice (preferably from a Gas Safe registered engineer for gas, or an OFTEC registered engineer for oil) before deciding which boiler is best for your home.

Don't install a boiler yourself. It must be installed by a qualified engineer and inspected regularly. It is not sufficient that the owner of the company be Gas Safe registered, the person fitting your boiler must be able to demonstrate that he/she is registered by showing ID before you permit access.

Once fitted you will need to have your system checked regularly. In the meantime you should know enough about the workings of the boiler to be able to spot any drop in water pressure which could damage your system.

You may wish to take out a service care agreement against any future problems with the system and be prepared for any unexpected emergencies.

If you haven't had your boiler replaced in the last 15 years you could do worse than replacing it with one of the new generation of high efficiency condensing combination boilers which could save you as much as 37p in every pound you spend on heating and hot water.*

*Source: SUDBUK boiler efficiency database, published as part of the Government's Energy Efficiency Best Practice Programme. Applies to energy-saving (condensing)boilers, depending on type of boiler being replaced and consumption. Based on the average life span of a boiler (15 years) in a standard three bedroom semi-detached house and on an average UK gas price of 1.41p/kWh as recommended by the Energy Saving Trust, December 2001.

Maintaining Your Heating System Tips From British Gas

• Ensure your central heating and gas appliances are serviced annually by a Gas Safe registered engineer.
• Never block or cover vents. Clear vents allow your gas appliances to breathe and burn safely and efficiently.
• Consider fitting a carbon monoxide detector in your property - one of these small, inexpensive devices could save your life. Maintained correctly, they will warn you if the carbon monoxide level in your home becomes dangerous.
• Although in the summer the weather may be warm and sunny, fire up your central heating system occasionally to keep it ticking over and prevent it from jamming when the cold sets in.
• Bleed your radiators every now and again to ensure they have no air in them. You'll know if they need bleeding as they may be cold at the top.

Types Of Boiler

Conventional Boilers

If you have a gravity heating system (with a water tank in the loft) then you'll need a conventional boiler. These use a traditional system which heats up a store of water before you need to use it, via a hot water cylinder and header tank

Condensing Boilers

Although more expensive than a conventional boiler a condensing boiler is highly efficient - using an extra heat exchanger to extract further heat from the water vapour produced in the combustion process, so very little heat is wasted.

Combination Boilers

For a flat or small house Combi Boilers are most suitable since they don't need to store water but instead heat the water as you use it.

Useful Links

There is no cylinder, no tank and no connecting pipe work, which saves space and reduces hot water costs. A combination boiler produces a near instantaneous supply of hot water on tap, 24 hours a day. Unlike conventional heating and hot water systems, a combination system does not store hot water.

British Gas
www.est.org.uk

The Boiler Efficiency Database
www.sedbuk.com

The Energy Saving Trust
The Energy Saving Trust

Gas Safe Register

www.gassaferegister.co.uk

DEFRA
www.defra.gov.uk

Worcester Boilers

Worcester has created a wide range of boilers so that there is one for every home if you are looking to upgrade your current boiler. They offer 3 main types of boiler which are Combi, Regular or System. They all have their benefits and some will be more suited to your home than others.

Combi

The combi boilers are the most common and the easiest to use because the heating and the water can be controlled via the boiler which will save on energy and keep the bills low! No separate water cylinder is needed in the house and therefore will be a great space saver. With the combi boiler being so simple the installation is easier and will again save money by installation being quick and easy.

If a household is using a combi boiler then they have the potential to run more than one to control different areas of the house (e.g. upstairs and downstairs boilers) so that the performance is improved by allowing more hot water around the household and greater control of the temperatures, also in case one boiler breaks down the other can take over.

Worcester’s combi boilers are all high efficiency boilers and are officially grade A rated by SEDBUK and have an efficiency of 90.4% maximum. The combi boilers on offer are all available in natural gas and LPG versions and come in a range of sizes so that you can choose the one that is perfect for your home. One of the most powerful combi boilers that Worcester offers is the Greenstar 42CDi which provides a maximum heat output of 30kW to the central heating and also has a ‘keep hot’ facility which allows for instantly hot water throughout the household.

The Greenstar Highflow 550CDi is an equally powerful combi boiler but is unique in the fact that is a floor mounted boiler so that you can easily slide it into place using the wheels and also keeps installations costs down by not having to buy wall fixing plates or any extra piping. Worcester have made their boilers flexible when they are being sited so that you can really choose where you want it! Combi boilers account for over half of the UK’s boilers and are still growing in popularity, Worcester’s boilers can be purchased at low prices from Fireplace Megastore.

Regular & System

Regular and system boilers are very similar in the way that they control the heating and the water temperature. They both provide heat for the central heating of the household and they also produce hot water to be stored in a cylinder unlike the combi boilers which supply hot water directly to the taps in the house.

With the regular and system boilers Worcester has made each product capable of working with Greenskies solar heating panels which makes it better for the environment and will also keep heating bills low.

The advantages of a system boiler over a regular boiler are that a system boiler already has the majority of components built in which will save on installation time and costs. A system boiler also pumps the hot water through the system to the radiators and to the cylinder which results in a faster response and more economical running costs.

Some of the best regular and system boilers available from Worcester are the Greenstar FS 30CDi Regular which has an efficiency of 90.5%, the highest natural gas efficiency from Worcester. Another good boiler is the Greenstar 24i System because of its compact design it provides more flexibility when being cited as well as having a high efficiency and maximum heat output.